Some children want to challenge themselves by learning a language different from ______ their parents speak at home.
| A．what | B．that | C．which | D．One |
Is this the reason _______ at the meeting for his carelessness in his work？
| A．he explained | B．what he explained | C．how he explained | D．why he explained |
All of the flowers now raised here have developed from those _______ in the forest.
| A．once they grew | B．they grew once | C．they once grew | D．once grew |
Our company will move to a tall building _______ we worked two years ago.
| A．where | B．when | C．that | D．which |
Our company will move to a tall building _______ has just been complete.
| A．which | B．when | C．how | D．where |
Our company will move to a tall building _______ we bought last month.
| A．which | B．when | C．how | D．where |